Cisco IOS XE Wireless Controller Software for the Catalyst 9000 Family CAPWAP Denial of Service Vulnerabilities

Vulnerability

Multiple vulnerabilities exist in the Control and Provisioning of Wireless Access Points (CAPWAP) protocol processing of Cisco IOS XE Software for Cisco Catalyst 9800 Series Wireless Controllers [1]. These flaws stem from insufficient validation of CAPWAP packets. Affected versions include various releases of Cisco IOS XE for the Catalyst 9800 series; specific vulnerable versions are detailed in the Cisco Security Advisory [1]. No authentication or special configuration is required to reach the vulnerable code path; a device with CAPWAP enabled is susceptible.

Exploitation

An unauthenticated, adjacent attacker can exploit these vulnerabilities by sending a single malformed CAPWAP packet to an affected device [1]. The attacker must be within layer-2 range of the device; no prior access or user interaction is needed. The crafted packet triggers the insufficient validation logic, leading to a crash and reload of the device.

Impact

Successful exploitation causes the affected device to crash and reload, resulting in a denial of service (DoS) condition [1]. This disrupts all wireless services provided by the controller until the device completes the reload process. No impact on confidentiality or integrity is described, but availability is fully compromised during the outage.

Mitigation

Cisco has released free software updates to address these vulnerabilities [1]. Customers should upgrade to the fixed Cisco IOS XE Software version as specified in the Cisco Security Advisory [1]. No workarounds are available; disabling CAPWAP is not feasible as it is required for normal operation. The vulnerabilities are not listed in CISA's Known Exploited Vulnerabilities (KEV) catalog as of the publication date.